The Chernobyl Tissue Bank -Coordinating Center Abstract The Chernobyl Tissue Bank was established in 1998 to collect, annotate and store biological samples from patients who were exposed in childhood and adolescence to radioiodine in fallout from the Chernobyl accident, and who subsequently have developed thyroid cancer. The bank currently contains material from 4500 patients, and all material is consented for use in research, including genomics. Biological samples are further processed and made available to scientists worldwide for research on the molecular mechanisms underlying development of thyroid cancer. The CTB also facilitates collection of samples for NCI funded epidemiological cohorts studies such as the Ukraine- American cohort. Sample collection is prospective and the CTB now contains a control population, resident in the same geographical areas, who have developed young onset thyroid cancer in the absence of radioiodine exposure, thus facilitating research into identifying biomarkers of radiation in an age- matched cohort. An estimated thyroid dose for each exposed individual is also provided by the CTB. The current application is for continued collection of samples in Ukraine, addition of further clinical data on treatment and outcome and further collation of research data. Recent research in adult thyroid cancer has suggested that addition of biomarkers to clinical annotation provides better risk stratification for patients. The CTB is the largest collection of samples from young onset thyroid cancer and is therefore ideally placed for studies into the role of biomarkers in risk stratification for young onset thyroid cancer. To facilitate this, the CTB is also in the process of collating data from research studies that have used material from the resource. This will enable initial in silico studies to be conducted to identify potential risk stratification biomarkers for validation in further studies. The funds sought in this application are to support the continuation and further development of this unique infrastructure. Elements of the infrastructure have potential for use in other large-scale tissue banking initiatives for cancer research.